Distinguishing Molecular Mechanical Action from Photothermal and Photodynamic Behavior

Molecular motors (MM) are molecular machines, or nanomachines, that rotate unidirectionally upon photostimulation and perform mechanical work on their environment. In the last several years, it has been shown that the photomechanical action of MM can be used to permeabilize lipid bilayers, thereby killing cancer cells and pathogenic microorganisms and controlling cell signaling. The work contributes to a growing acknowledgement that the molecular actuation characteristic of these systems is useful for various applications in biology. However, the mechanical effects of molecular motion on biological materials are difficult to disentangle from photodynamic and photothermal action, which are also present when a light-absorbing fluorophore is irradiated with light. Here, an overview of the key methods used by various research groups to distinguish the effects of photomechanical, photodynamic, and photothermal action is provided. It is anticipated that this discussion will be helpful to the community seeking to use MM to develop new and distinctive medical technologies that result from mechanical disruption of biological materials.

Nonlethal Molecular Nanomachines Potentiate Antibiotic Activity Against Gram-Negative Bacteria by Increasing Cell Permeability and Attenuating Efflux

Antibiotic resistance is a pressing public health threat. Despite rising resistance, antibiotic development, especially for Gram-negative bacteria, has stagnated. As the traditional antibiotic research and development pipeline struggles to address this growing concern, alternative solutions become imperative. Synthetic molecular nanomachines (MNMs) are molecular structures that rotate unidirectionally in a controlled manner in response to a stimulus, such as light, resulting in a mechanical action that can propel molecules to drill into cell membranes, causing rapid cell death. Due to their broad destructive capabilities, clinical translation of MNMs remains challenging. Hence, here, we explore the ability of nonlethal visible-light-activated MNMs to potentiate conventional antibiotics against Gram-negative bacteria. Nonlethal MNMs enhanced the antibacterial activity of various classes of conventional antibiotics against Gram-negative bacteria, including those typically effective only against Gram-positive strains, reducing the antibiotic concentration required for bactericidal action. Our study also revealed that MNMs bind to the negatively charged phospholipids of the bacterial inner membrane, leading to permeabilization of the cell envelope and impairment of efflux pump activity following light activation of MNMs. The combined effects of MNMs on membrane permeability and efflux pumps resulted in increased antibiotic accumulation inside the cell, reversing antibiotic resistance and attenuating its development. These results identify nonlethal MNMs as pleiotropic antibiotic enhancers or adjuvants. The combination of MNMs with traditional antibiotics is a promising strategy against multidrug-resistant Gram-negative infections. This approach can reduce the amount of antibiotics needed and slow down antibiotic resistance development, thereby preserving the effectiveness of our current antibiotics.

Microbiological evaluation of homemade mayonnaise and self-serve acai sold in Araguaína, Tocantins

Foodborne diseases are common illnesses caused by the consumption of food contaminated with microorganisms, such as viruses, fungi, bacteria, and protozoa. Every year, 600 million people become ill and 420,000 people die as a result of consuming contaminated food. Therefore, food safety is an important issue. In this study, samples of homemade spiced mayonnaise and self-serve acai sold in the city of Araguaína, Tocantins, Brazil were analyzed for microbiological contaminants. Acai was collected from 10 stores, one sample from each store, and tested for mold, yeast, and coliforms, as well as coliform identification and total and thermotolerant coliform counts. Mayonnaise was collected from 20 snack bars, one sample from each. These samples were inoculated on MacConkey and Salmonella Shigella agar plates, and the plates were analyzed for growth. Salmonella spp. were detected in some Mayonnaise samples, and coliforms were detected in all acai samples; 60% of samples had thermotolerant coliforms, and only 40% were within the limits established by ANVISA. The collected samples of mayonnaise and acai were contaminated with molds and yeasts above the established limit of 103 CFU/g. Thus, the analyzed mayonnaise and acai samples were contaminated and unfit for consumption, demonstrating the importance of hygienic-sanitary measures in food handling.

Molecular machines stimulate intercellular calcium waves and cause muscle contraction

Intercellular calcium waves (ICW) are complex signalling phenomena that control many essential biological activities, including smooth muscle contraction, vesicle secretion, gene expression and changes in neuronal excitability. Accordingly, the remote stimulation of ICW could result in versatile biomodulation and therapeutic strategies. Here we demonstrate that light-activated molecular machines (MM)-molecules that perform mechanical work on the molecular scale-can remotely stimulate ICW. MM consist of a polycyclic rotor and stator that rotate around a central alkene when activated with visible light. Live-cell calcium-tracking and pharmacological experiments reveal that MM-induced ICW are driven by the activation of inositol-triphosphate-mediated signalling pathways by unidirectional, fast-rotating MM. Our data suggest that MM-induced ICW can control muscle contraction in vitro in cardiomyocytes and animal behaviour in vivo in Hydra vulgaris. This work demonstrates a strategy for directly controlling cell signalling and downstream biological function using molecular-scale devices.

Damage dynamics and the role of chance in the timing of E. coli cell death

Genetically identical cells in the same stressful condition die at different times. The origin of this stochasticity is unclear; it may arise from different initial conditions that affect the time of demise, or from a stochastic damage accumulation mechanism that erases the initial conditions and instead amplifies noise to generate different lifespans. To address this requires measuring damage dynamics in individual cells over the lifespan, but this has rarely been achieved. Here, we used a microfluidic device to measure membrane damage in 635 carbon-starved Escherichia coli cells at high temporal resolution. We find that initial conditions of damage, size or cell-cycle phase do not explain most of the lifespan variation. Instead, the data points to a stochastic mechanism in which noise is amplified by a rising production of damage that saturates its own removal. Surprisingly, the relative variation in damage drops with age: cells become more similar to each other in terms of relative damage, indicating increasing determinism with age. Thus, chance erases initial conditions and then gives way to increasingly deterministic dynamics that dominate the lifespan distribution.

Visible-Light-Activated Molecular Machines Kill Fungi by Necrosis Following Mitochondrial Dysfunction and Calcium Overload

Invasive fungal infections are a growing public health threat. As fungi become increasingly resistant to existing drugs, new antifungals are urgently needed. Here, it is reported that 405-nm-visible-light-activated synthetic molecular machines (MMs) eliminate planktonic and biofilm fungal populations more effectively than conventional antifungals without resistance development. Mechanism-of-action studies show that MMs bind to fungal mitochondrial phospholipids. Upon visible light activation, rapid unidirectional drilling of MMs at ≈3 million cycles per second (MHz) results in mitochondrial dysfunction, calcium overload, and ultimately necrosis. Besides their direct antifungal effect, MMs synergize with conventional antifungals by impairing the activity of energy-dependent efflux pumps. Finally, MMs potentiate standard antifungals both in vivo and in an ex vivo porcine model of onychomycosis, reducing the fungal burden associated with infection.

Ageing, Metabolic Dysfunction, and the Therapeutic Role of Antioxidants

The gradual ageing of the world population has been accompanied by a dramatic increase in the prevalence of obesity and metabolic diseases, especially type 2 diabetes. The adipose tissue dysfunction associated with ageing and obesity shares many common physiological features, including increased oxidative stress and inflammation. Understanding the mechanisms responsible for adipose tissue dysfunction in obesity may help elucidate the processes that contribute to the metabolic disturbances that occur with ageing. This, in turn, may help identify therapeutic targets for the treatment of obesity and age-related metabolic disorders. Because oxidative stress plays a critical role in these pathological processes, antioxidant dietary interventions could be of therapeutic value for the prevention and/or treatment of age-related diseases and obesity and their complications. In this chapter, we review the molecular and cellular mechanisms by which obesity predisposes individuals to accelerated ageing. Additionally, we critically review the potential of antioxidant dietary interventions to counteract obesity and ageing.

Hemithioindigo-Based Visible Light-Activated Molecular Machines Kill Bacteria by Oxidative Damage

Antibiotic resistance is a growing health threat. There is an urgent and critical need to develop new antimicrobial modalities and therapies. Here, a set of hemithioindigo (HTI)-based molecular machines capable of specifically killing Gram-positive bacteria within minutes of activation with visible light (455 nm at 65 mW cm^-2 ) that are safe for mammalian cells is described. Importantly, repeated exposure of bacteria to HTI does not result in detectable development of resistance. Visible light-activated HTI kill both exponentially growing bacterial cells and antibiotic-tolerant persister cells of various Gram-positive strains, including methicillin-resistant S. aureus (MRSA). Visible light-activated HTI also eliminate biofilms of S. aureus and B. subtilis in as little as 1 h after light activation. Quantification of reactive oxygen species (ROS) formation and protein carbonyls, as well as assays with various ROS scavengers, identifies oxidative damage as the underlying mechanism for the antibacterial activity of HTI. In addition to their direct antibacterial properties, HTI synergize with conventional antibiotics in vitro and in vivo, reducing the bacterial load and mortality associated with MRSA infection in an invertebrate burn wound model. To the best of the authors' knowledge, this is the first report on the antimicrobial activity of HTI-based molecular machines.

Light-activated molecular machines are fast-acting broad-spectrum antibacterials that target the membrane

The increasing occurrence of antibiotic-resistant bacteria and the dwindling antibiotic research and development pipeline have created a pressing global health crisis. Here, we report the discovery of a distinctive antibacterial therapy that uses visible (405 nanometers) light-activated synthetic molecular machines (MMs) to kill Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, in minutes, vastly outpacing conventional antibiotics. MMs also rapidly eliminate persister cells and established bacterial biofilms. The antibacterial mode of action of MMs involves physical disruption of the membrane. In addition, by permeabilizing the membrane, MMs at sublethal doses potentiate the action of conventional antibiotics. Repeated exposure to antibacterial MMs is not accompanied by resistance development. Finally, therapeutic doses of MMs mitigate mortality associated with bacterial infection in an in vivo model of burn wound infection. Visible light-activated MMs represent an unconventional antibacterial mode of action by mechanical disruption at the molecular scale, not existent in nature and to which resistance development is unlikely.

New Endoscopic Solutions in Managing Phlegmonous Esophagitis

A 48-year-old woman was admitted in the emergency department due to epigastric pain, nausea, vomiting, and cough. She presented with fever and increased inflammatory parameters. A thoracoabdominal computed tomography (CT) was performed and revealed thickening of the gastric fundus and esophagus, with an apparent laceration in esophageal mucosa and associated dissection of esophageal wall. In upper endoscopy (UE), a bulging of esophageal and gastric walls was observed, with an ulceration in proximal esophagus, suggestive of a perforation. After multidisciplinary discussion, a minimally invasive endoscopic approach was decided. Internal esophageal drainage (IED) was assured with performance of some incisions with Dual-knife® (Olympus, Tokyo) along the mucosal and submucosal layers in the esophagus. During the incision, extravasation of pus was evident. One week later, due to clinical worsening and evidence of esophageal perforation in CT scan, UE was repeated. We confirmed esophageal perforation with visualization of two millimetric defects in the proximal esophagus. Significant bulging of the gastric fundus and body was also observed. IED was repeated with mucosal incision of the gastric bulging using Needle-Cut 3V® (Olympus, Tokyo), with extravasation of a significant quantity of pus. We decided to proceed to endoscopic vacuum therapy that was performed with sponge placement in the esophageal lumen (Endosponge®, B. Braun, Melsungen, Germany). UE was repeated 1 week later with sponge removal and confirmation of resolution of esophageal perforation. An improvement of the thickening of gastric fundus and body was also seen. One month later after admission, the patient was discharged home, eating normally, and remains well in the follow-up.

Endoscopic radiofrequency ablation for palliative treatment of hilar cholangiocarcinoma

BACKGROUND AND AIMS

Recent data support a role for endoscopic radiofrequency ablation (RFA) in unresectable cholangiocarcinoma by improving stent patency and overall survival.

METHODS

We describe 3 patients with inoperable cholangiocarcinoma with jaundice and cholestasis who were recommended palliative chemotherapy. They underwent endoscopic retrograde cholangiopancreatography with single-operator cholangioscope and intraductal RFA.

RESULTS

The procedures were performed without adverse events in all patients, with clinical and analytical improvement 1 month later.

CONCLUSIONS

RFA is a promising and safe palliative treatment in patients with unresectable cholangiocarcinoma.

Development of an Online App to Predict Post-Endoscopic Retrograde Cholangiopancreatography Adverse Events Using a Single-Center Retrospective Cohort

INTRODUCTION

Endoscopic retrograde cholangiopancreatography (ERCP) is a technically demanding procedure with a high risk for adverse events (AEs).

AIM

evaluate patient- and procedure-related risk factors for ERCP-related AEs and develop an online app to estimate risk of AEs.

METHODS

retrospective study of 1,491 consecutive patients who underwent 1,991 ERCPs between 2012 and 2017 was conducted. AEs definition and severity were classified according to most recent ESGE guidelines. Each variable was tested for association with occurrence of overall AEs, post-ERCP pancreatitis (PEP) and cholangitis. For each outcome, 2 regression models were built, from which an online Shiny-based app was created.

RESULTS

Overall AE rate was 15.3%; in 19 procedures, >1 AE occurred. Main post-ERCP AE was PEP (7.5%), followed by cholangitis (4.9%), bleeding (1.3%), perforation (1%), cardiopulmonary events (0.9%), and cholecystitis (0.3%). Seventy-eight percent of AEs were mild/moderate; of severe (n = 55) and fatal (n = 20) AEs, more than half were related to infection, cardiac/pulmonary AEs, and perforation. AE-related mortality rate was 1%. When testing precannulation, procedural covariates, and ERCP findings, AE occurrence was associated with age (odds ratio [OR] 0.991), previous PEP (OR 2.198), ERCP complexity grade III/IV (OR 1.924), standard bile duct cannulation (OR 0.501), sphincterotomy (OR 1.441), metal biliary stent placement (OR 2.014), periprocedural bleeding (OR 3.024), and biliary duct lithiasis (OR 0.673).

CONCLUSION

Our app may allow an optimization of the patients' care, by helping in the process of decision-making, not only regarding patient or endoscopist's selection but also definition of an adequate and tailored surveillance plan after the procedure.

Light-based technologies for management of COVID-19 pandemic crisis

The global dissemination of the novel coronavirus disease (COVID-19) has accelerated the need for the implementation of effective antimicrobial strategies to target the causative agent SARS-CoV-2. Light-based technologies have a demonstrable broad range of activity over standard chemotherapeutic antimicrobials and conventional disinfectants, negligible emergence of resistance, and the capability to modulate the host immune response. This perspective article identifies the benefits, challenges, and pitfalls of repurposing light-based strategies to combat the emergence of COVID-19 pandemic.

The value of antimicrobial peptides in the age of resistance

Accelerating growth and global expansion of antimicrobial resistance has deepened the need for discovery of novel antimicrobial agents. Antimicrobial peptides have clear advantages over conventional antibiotics which include slower emergence of resistance, broad-spectrum antibiofilm activity, and the ability to favourably modulate the host immune response. Broad bacterial susceptibility to antimicrobial peptides offers an additional tool to expand knowledge about the evolution of antimicrobial resistance. Structural and functional limitations, combined with a stricter regulatory environment, have hampered the clinical translation of antimicrobial peptides as potential therapeutic agents. Existing computational and experimental tools attempt to ease the preclinical and clinical development of antimicrobial peptides as novel therapeutics. This Review identifies the benefits, challenges, and opportunities of using antimicrobial peptides against multidrug-resistant pathogens, highlights advances in the deployment of novel promising antimicrobial peptides, and underlines the needs and priorities in designing focused development strategies taking into account the most advanced tools available.

Temporal scaling of aging as an adaptive strategy of Escherichia coli

Natural selection is thought to shape the evolution of aging patterns, although how life-history trajectories orchestrate the inherently stochastic processes associated with aging is unclear. Tracking clonal growth-arrested Escherichia coli cohorts in an homogeneous environment at single-cell resolution, we demonstrate that the Gompertz law of exponential mortality characterizes bacterial lifespan distributions. By disentangling the rate of aging from age-independent components of longevity, we find that increasing cellular maintenance through the general stress pathway reduces the aging rate and rescales the lifespan distribution at the expense of growth. This trade-off between aging and growth underpins the evolutionary tuning of the general stress response pathway in adaptation to the organism's feast-or-famine lifestyle. It is thus necessary to involve both natural selection and stochastic physiology to explain aging patterns.

Infectious proctitis: a necessary differential diagnosis in ulcerative colitis

INTRODUCTION

In the last years, there was a rising in the incidence of sexually transmitted infections, including proctitis. Infectious proctitis (IP), mainly caused by agents like Neisseria gonorrhea and Chlamydia trachomatis, is an entity that should be considered when patients with suspected inflammatory bowel disease (IBD) are approached, mainly if they have risk factors such as anal intercourse.

CLINICAL CASES/DISCUSSION

The symptoms of IP, like rectal blood, mucous discharge, and anorectal pain, may appear in other causes of proctitis, like IBD. Therefore, to establish the diagnosis, it is crucial to take a detailed history and perform a physical examination, with the diagnosis being supported by complementary tests such as rectosigmoidoscopy, histology, serology, and culture. Depending on the etiology, treatment of IP is based in antibiotics or antivirals, which may be empirically initiated. Co-infections, mainly those that are sexually transmitted, and HIV should be tested and sexual partners should be treated, accordingly. In this article, the authors report three cases of IP, referent to three different patients, and review the initial approach required in cases where there is a clinical and/or endoscopic suspicion of this pathology.

Design and Application of a Low pH Upflow Biofilm Sulfidogenic Bioreactor for Recovering Transition Metals From Synthetic Waste Water at a Brazilian Copper Mine

A sulfidogenic bioreactor, operated at low pH (4–5), was set up and used to remove transition metals (copper, nickel, cobalt, and zinc) from a synthetic mine water, based on the chemistry of a moderately acidic (pH 5) drainage stream at an operating copper mine in Brazil. The module was constructed as an upflow biofilm reactor, with microorganisms immobilized on porous glass beads, and was operated continuously for 462 days, during which time the 2 L bioreactor processed >2,000 L of synthetic mine water. The initial treatment involved removing copper (the most abundant metal present) off-line in a stream of H₂S-containing gas generated by the bioreactor, which caused the synthetic mine water pH to fall to 2.1. The copper-free water was then amended with glycerol (the principal electron donor), yeast extract and basal salts, and pumped directly into the bioreactor where the other three transition metals were precipitated (also as sulfides), concurrent with increased solution pH. Although some acetate was generated, most of the glycerol fed to the bioreactor was oxidized to carbon dioxide, and was coupled to the reduction of sulfate to hydrogen sulfide. No archaea or eukaryotes were detected in the bioreactor microbial community, which was dominated by acidophilic sulfate-reducing Firmicutes (Peptococcaceae strain CEB3 and Desulfosporosinus acididurans); facultatively anaerobic non-sulfidogens (Acidithiobacillus ferrooxidans and Actinobacterium strain AR3) were also found in small relative abundance. This work demonstrated how a single low pH sulfidogenic bioreactor can be used to remediate a metal-rich mine water, and to facilitate the recovery (and therefore recycling) of target metals. The system was robust, and was operated empirically by means of pH control. Comparison of costs of the main consumables (glycerol and yeast extract) and the values of the metals recovered showed a major excess of the latter, supporting the view that sulfidogenic biotechnology can have significant economic as well as environmental advantages over current approaches used to remediate mine waters which produce secondary toxic wastes and fail to recover valuable metals.

Correction to: Cryptosporidium Spp. Contamination in Perna perna Mussels Destined for Human Consumption in Southeastern Rio de Janeiro, Brazil

The original version of this article unfortunately contained a mistake.

Cryptosporidium spp. Contamination in Perna perna Mussels Destined for Human Consumption in Southeastern Rio de Janeiro, Brazil

Cryptosporidium spp. has been recognized as an important pathogen. As bivalve mollusks are noted as potential sources of several pathogens due to their consumption as foodstuffs, the aim of this study was to investigate the occurrence of Cryptosporidium spp. oocysts in Perna perna mussels and in seawater samples from a mussel farm in Southeastern Brazil, where mussels are grown directly in the sea, attached to ropes. Oocysts were observed by microscopy and confirmed by an enzyme-linked immunosorbent assay. Oocysts were present in mussel gills and GI tracts, as well as in the seawater. Of the 100 females, 10% and 11% showed contaminated GI tracts and gills, respectively, while this rate was lower in males, at 5% and 8.9%. Oocysts were present in higher amounts in the GI tract compared to gills and water. Contamination of the study area is apparent, leading to public health risks. More in-depth studies are needed, including molecular investigations, to identify Cryptosporidium species in mussels, as well as the implementation of monitoring actions in animals destined for human consumption.

Anti-influenza neuraminidase inhibitor oseltamivir phosphate induces canine mammary cancer cell aggressiveness

Oseltamivir phosphate is a widely used anti-influenza sialidase inhibitor. Sialylation, governed by sialyltransferases and sialidases, is strongly implicated in the oncogenesis and progression of breast cancer. In this study we evaluated the biological behavior of canine mammary tumor cells upon oseltamivir phosphate treatment (a sialidase inhibitor) in vitro and in vivo. Our in vitro results showed that oseltamivir phosphate impairs sialidase activity leading to increased sialylation in CMA07 and CMT-U27 canine mammary cancer cells. Surprisingly, oseltamivir phosphate stimulated, CMT-U27 cell migration and invasion capacity in vitro, in a dose-dependent manner. CMT-U27 tumors xenograft of oseltamivir phosphate-treated nude mice showed increased sialylation, namely α2,6 terminal structures and SLe(x) expression. Remarkably, a trend towards increased lung metastases was observed in oseltamivir phosphate-treated nude mice. Taken together, our findings revealed that oseltamivir impairs canine mammary cancer cell sialidase activity, altering the sialylation pattern of canine mammary tumors, and leading, surprisingly, to in vitro and in vivo increased mammary tumor aggressiveness.

Contribution of chemical water properties to the differential responses of bacterioneuston and bacterioplankton to ultraviolet-B radiation

The surface microlayer (SML) is characterized by different physicochemical properties from underlying waters (UW). However, whether these differences in abiotic factors underlie the distinct sensitivity of bacterioneuston (i.e. SML bacteria) and bacterioplankton to environmental stressors remains to be addressed. We investigated the contribution of abiotic factors to the UV-B sensitivity of bacterioneuston and bacterioplankton. Nutrients (especially nitrogen and phosphate) emerged as important determinants of bacterial UV-B sensitivity. The role of particles, nutrients, and dissolved organic components on bacterial UV-B sensitivity was further evaluated using dilution cultures. Filtered samples were twofold more UV sensitive than unfiltered samples, suggesting a UV-protective effect of particles. High nutrient concentrations attenuated bacterial UV-B sensitivity (up to 40%), compared with unamended conditions, by influencing bacterial physiology and/or community composition. Suspending cells in natural water, particularly from the SML, also attenuated UV-B sensitivity (up to 23%), compared with suspension in an artificial mineral solution. Bioassays using Pseudomonas sp. strain NT5I1.2B revealed that chemical water properties influence UV-induced oxidative damage. UV-B sensitivity was associated with high cell-specific activities. The chemical environment of the SML and UW influences UV-B effects on the corresponding bacterial communities. Maintaining low cell activities might be advantageous in stressful environments, like the SML.

Effects of UV radiation on the lipids and proteins of bacteria studied by mid-infrared spectroscopy

Knowledge of the molecular effects of UV radiation (UVR) on bacteria can contribute to a better understanding of the environmental consequences of enhanced UV levels associated with global climate changes and will help to optimize UV-based disinfection strategies. In the present work, the effects of exposure to UVR in different spectral regions (UVC, 100-280 nm; UVB, 280-320 nm; and UVA, 320-400 nm) on the lipids and proteins of two bacterial strains ( Acinetobacter sp. strain PT5I1.2G and Pseudomonas sp. strain NT5I1.2B) with distinct UV sensitivities were studied by mid-infrared spectroscopy. Exposure to UVR caused an increase in methyl groups associated with lipids, lipid oxidation, and also led to alterations in lipid composition, which were confirmed by gas chromatography. Additionally, mid-infrared spectroscopy revealed the effects of UVR on protein conformation and protein composition, which were confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), oxidative damage to amino acids, and changes in the propionylation, glycosylation and/or phosphorylation status of cell proteins. Differences in the targets of UVR in the two strains tested were identified and may explain their discrepant UV sensitivities. The significance of the results is discussed from an ecological standpoint and with respect to potential improvements in UV-based disinfection technologies.

Interactive effects of global climate change and pollution on marine microbes: the way ahead

Global climate change has the potential to seriously and adversely affect marine ecosystem functioning. Numerous experimental and modeling studies have demonstrated how predicted ocean acidification and increased ultraviolet radiation (UVR) can affect marine microbes. However, researchers have largely ignored interactions between ocean acidification, increased UVR and anthropogenic pollutants in marine environments. Such interactions can alter chemical speciation and the bioavailability of several organic and inorganic pollutants with potentially deleterious effects, such as modifying microbial-mediated detoxification processes. Microbes mediate major biogeochemical cycles, providing fundamental ecosystems services such as environmental detoxification and recovery. It is, therefore, important that we understand how predicted changes to oceanic pH, UVR, and temperature will affect microbial pollutant detoxification processes in marine ecosystems. The intrinsic characteristics of microbes, such as their short generation time, small size, and functional role in biogeochemical cycles combined with recent advances in molecular techniques (e.g., metagenomics and metatranscriptomics) make microbes excellent models to evaluate the consequences of various climate change scenarios on detoxification processes in marine ecosystems. In this review, we highlight the importance of microbial microcosm experiments, coupled with high-resolution molecular biology techniques, to provide a critical experimental framework to start understanding how climate change, anthropogenic pollution, and microbiological interactions may affect marine ecosystems in the future.

Growth conditions influence UVB sensitivity and oxidative damage in an estuarine bacterial isolate

The dose-dependent variation of oxidative cellular damage imposed by UVB exposure in a representative estuarine bacterial strain, Pseudomonas sp. NT5I1.2B, was studied at different growth phases (mid-exponential, late-exponential, and stationary), growth temperatures (15 °C and 25 °C) and growth media (nutrient-rich Tryptic Soy Broth [TSB] and nutrient-poor M9). Survival and markers of oxidative damage (lipid peroxidation, protein carbonylation, DNA strand breakage, and DNA-protein cross-links) were monitored during exposure to increasing UVB doses (0-60 kJ m(-2)). Oxidative damage did not follow a clear linear dose-dependent pattern, particularly at high UVB doses (>10 kJ m(-2)), suggesting a dynamic interaction between damage induction and repair during irradiation and/or saturation of oxidative damage. Survival of stationary phase cells generally exceeded that of exponential phase cells by up to 33.5 times; the latter displayed enhanced levels of DNA-protein cross-links (up to 15.6-fold) and protein carbonylation (up to 6.0-fold). Survival of mid-exponential phase cells was generally higher at 15 °C than at 25 °C (up to 6.6-fold), which was accompanied by lower levels of DNA strand breaks (up to 4000-fold), suggesting a temperature effect on reactive oxygen species (ROS) generation and/or ROS interaction with cellular targets. Survival under medium-high UVB doses (>10 kJ m(-2)) was generally higher (up to 5.4-fold) in cells grown in TSB than in M9. These results highlight the influence of growth conditions preceding irradiation on the extent of oxidative damage induced by UVB exposure in bacteria.

Psychological adjustment to diabetes mellitus: highlighting self-integration and self-regulation

Psychological adjustment to any chronic disease, such as diabetes mellitus, concerns self-view rearrangement toward self-integrity and self-regulation. Both distance between self and disease paired with positive and negative new identities may contribute to adaptation to diabetes. The present investigation aimed to detect main trends on self-management in patients with both diabetes types within a self-regulatory framework. Sample consisted of 121 adult patients with both diabetes types. Answer to question about having diabetes or being a diabetic was combined with self-benefices or self-damages concerning diabetes in a 2 × 2 combination. Psychological adjustment to diabetes, anxiety and depression were evaluated among subgroups. Almost 16% of patients had any benefit with diabetes and a better psychological adjustment than patients reporting losses. Type 1 diabetes answered more "being diabetic" and type 2 "having diabetes". Education was positively associated with profits with diabetes. Patients referring "to have diabetes" and profits had the best diabetes psychological adjustment. Distance between self and diabetes does not seem to relate to psychological adjustment. Type 1 diabetes patients are likely to identify more with their disease comparing with type 2 diabetes, independently from gains or losses associated with diabetes. Better psychological adjustment related to more education and positivity highlights future interest on working with gains in diabetes patient education, fostering patient self-growth, self-integration and resilience.

Wavelength dependence of biological damage induced by UV radiation on bacteria

The biological effects of UV radiation of different wavelengths (UVA, UVB and UVC) were assessed in nine bacterial isolates displaying different UV sensitivities. Biological effects (survival and activity) and molecular markers of oxidative stress [DNA strand breakage (DSB), generation of reactive oxygen species (ROS), oxidative damage to proteins and lipids, and the activity of antioxidant enzymes catalase and superoxide dismutase] were quantified and statistically analyzed in order to identify the major determinants of cell inactivation under the different spectral regions. Survival and activity followed a clear wavelength dependence, being highest under UVA and lowest under UVC. The generation of ROS, as well as protein and lipid oxidation, followed the same pattern. DNA damage (DSB) showed the inverse trend. Multiple stepwise regression analysis revealed that survival under UVA, UVB and UVC wavelengths was best explained by DSB, oxidative damage to lipids, and intracellular ROS levels, respectively.

Contribution of reactive oxygen species to UV-B-induced damage in bacteria

The present work aimed to identify the reactive oxygen species (ROS) produced during UV-B exposure and their biochemical targets, in a set of bacterial isolates displaying different UV susceptibilities. For that, specific exogenous ROS scavengers (catalase/CAT, superoxide dismutase/SOD, sodium azide and mannitol) were used. Biological effects were assessed from total bacterial number, colony counts and heterotrophic activity (glucose uptake and respiration). DNA strand breakage, ROS generation, oxidative damage to proteins and lipids were used as markers of oxidative stress. Sodium azide conferred a statistically significant protection in terms of lipid oxidation and cell survival, suggesting that singlet oxygen might play an important role in UV-B induced cell inactivation. Mannitol exerted a significant protection against DNA strand breakage and protein carbonylation, assigning hydroxyl radicals to DNA and protein damage. The addition of exogenous CAT and SOD significantly protected the capacity for glucose uptake and respiration, suggesting that superoxide and H(2)O(2) are involved in the impairment of activity during UV-B exposure. The observation that amendment with ROS scavengers can sometimes also exert a pro-oxidant effect suggests that the intracellular oxidant status of the cell ultimately determines the efficiency of antioxidant defenses.

Impact of organic and inorganic nanomaterials in the soil microbial community structure

In this study the effect of organic and inorganic nanomaterials (NMs) on the structural diversity of the soil microbial community was investigated by Denaturing Gradient Gel Electrophoresis, after amplification with universal primers for the bacterial region V6-V8 of 16S rDNA. The polymers of carboxylmethyl-cellulose (CMC), of hydrophobically modified CMC (HM-CMC), and hydrophobically modified polyethylglycol (HM-PEG); the vesicles of sodium dodecyl sulphate/didodecyl dimethylammonium bromide (SDS/DDAB) and of monoolein/sodium oleate (Mo/NaO); titanium oxide (TiO(2)), titanium silicon oxide (TiSiO(4)), CdSe/ZnS quantum dots, gold nanorods, and Fe/Co magnetic fluid were the NMs tested. Soil samples were incubated, for a period of 30 days, after being spiked with NM suspensions previously characterized by Dynamic Light Scattering (DLS) or by an ultrahigh-resolution scanning electron microscope (SEM). The analysis of similarities (ANOSIM) of DGGE profiles showed that gold nanorods, TiO(2), CMC, HM-CMC, HM-PEG, and SDS/DDAB have significantly affected the structural diversity of the soil bacterial community.

Bacteriophages with potential for inactivation of fish pathogenic bacteria: survival, host specificity and effect on bacterial community structure

Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

Evaluating seasonal dynamics of bacterial communities in marine fish aquaculture: a preliminary study before applying phage therapy

The increasing problem of antibiotic resistance in common pathogenic bacteria and the concern about the spreading of antibiotics in the environment bring the need to find new methods to control fish pathogens. Phage therapy represents a potential alternative to antibiotics, but its use in aquaculture requires a detailed understanding of bacterial communities, namely of fish pathogenic bacteria. Therefore, in this study the seasonal dynamics of the overall bacterial communities, microbiological water quality and disease-causing bacteria were followed in a marine aquaculture system of Ria de Aveiro (Portugal). Analysis of the bacterial diversity of the water samples by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments indicates that the bacterial community structure varied seasonally, showing a higher complexity during the warm season. The diversity of the main fish pathogenic bacteria, assessed by DGGE targeting the Vibrio genus, showed lower seasonal variation, with new dominating populations appearing mainly in the spring. Bacterial indicators, faecal coliforms and enterococci, enumerated by the filter-membrane method, also varied seasonally. The fluorescent in situ hybridization (FISH) results showed that the specific groups of bacteria varied during the study period and that the non-indigenous Enterobactereaceae family was the most abundant group followed by Vibrio and Aeromonas. The seasonal variation detected in terms of density and structure of total and pathogenic bacterial communities demonstrates the need for a careful monitoring of water through the year in order to select the suitable phages to inactivate fish pathogenic bacteria. The spring season seems to be the critical time period when phage therapy should be applied.

Effects of monospecific banks of salt marsh vegetation on sediment bacterial communities

The aim of this study was to understand if two species of salt marsh plants, widely distributed in European estuaries (Spartina maritima and Halimione portulacoides) differently influence the distribution, activity, and metabolic physiology of sediment bacterial communities in monospecific banks, in comparison with uncolonized sediment (control). Microbiological descriptors of abundance and activity were assessed along vertical profiles of sediments. Rates of activity of the extracellular enzymes beta-glucosidase, alpha-glucosidase, aminopeptidase, arylsulfatase, and phosphatase were generally higher in the vegetation banks in relation to control sediments where they were also less variable with depth. This is interpreted as an indirect effect related to supply of plant-derived polymeric substrates for bacterial growth. Parameters related to sediment texture (grain size, percent of fines or water content) showed significant relations with cell abundance or maximum hydrolysis rates, pointing to an indirect effect of plant colonization exerted through the modification of sediment physical properties. The profiles of utilization of sole-carbon-source (Biolog Ecoplates) showed that only the communities from the upper sediment layer of the S. maritima and the H. portulacoides banks exhibit consistent differences in terms of physiological profiles. Bacterial communities in control sediments exhibited the lowest physiological variability between surface and sub-surface communities. The results indicate that microbial colonization and organic matter decomposition are enhanced under the influence of salt marsh plants and confirm that plant coverage is a major determinant of the processes of organic matter recycling in intertidal estuarine sediments.

[Core needle biopsy of papillary breast lesions: impact on patient management]

OBJECTIVES

To evaluate the clinical and radiological presentations of papillary breast lesions and to evaluate the performance of core needle breast biopsy in papillary lesions.

MATERIAL AND METHODS

We retrospectively studied 55 papillary breast lesions in 46 patients aged 28 to 87 years diagnosed using core needle biopsy in the period 1994-2005. We reviewed the clinical and radiological presentations of the lesions, the findings at histological study after percutaneous biopsy, and the correlation of these findings with those of the surgical biopsy (44 cases) and/or radiological follow-up (42 cases).

RESULTS

The most common mammographic presentation was circumscribed or ill-defined, single or multiple nodules. Ill-defined lesions were significantly associated with malignancy (p < 0.05). The results of the percutaneous biopsy were: benign papillary lesion (n = 32), papillary lesion with atypia (n = 9), and malignant papillary lesion (n = 14). The diagnostic accuracy of core needle biopsy calculated from the 44 cases with surgical confirmation was: sensitivity 63%, specificity 100%, predictive positive value 100%, predictive negative value 73%, and rate of underestimation 25%. During follow-up, increased lesion size or the appearance of new lesions was seen in four patients.

CONCLUSIONS

The diagnosis can be suspected in cases of postmenopausal patients with multiple circumscribed or ill-defined, solid or mixed lesions at ultrasound study. Although the finding of an invasive malignant papillary lesion after percutaneous biopsy enables treatment to be planned, in the remaining situations (benign papillary lesion, with atypia, or carcinoma in situ) underestimation is common and the lesion should be surgically excised. Vacuum-assisted biopsy systems might improve these results.

Urban ants and transportation of nosocomial bacteria

Many ant species displaying synanthropic behavior that have successfully dispersed in urban areas can cause problems in hospitals by acting as bacterial vectors. In this study, we encountered bacteria on ants collected at the Universidade Federal de Uberlândia hospital, in the campus and at households nearby. The ants were identified as Tapinoma melanocephalum (Fabricius) and Camponotus vittatus (Forel) (Hymenoptera: Formicidae) and the bacterial strains found here belong to the group of the coagulase-positive staphylococcus, coagulase-negative staphylococcus and gram negative bacilli, including antimicrobial drug-resistant strains. An investigation of the bacteria found in the ants and in the environment revealed that some ants carried non-isolated bacteria from the same environment and with high levels of resistance, evidencing the transmission potential of these insects.

Some Digenea parasites of tunny from the coast of Rio de Janeiro State, Brazil

Rhipidocotyle pentagonum (Ozaki, 1924) is reported for the first time in South America parasitizing Auxis thazard and in a new host Katsuwonus pelamis. Tergestia laticollis (Rudolphi, 1819) is reported for the first time in South America and in Thunnus albacares, representing a new host record. Copiatestes filiferus (Leuckart, in Sars, 1885) is recorded for the first time in Brazil and in Thunnus albacares, another new host record. Tetrochetus coryphaenae (Yamaguti, 1934) is presented for the first time in Brazil parasitizing Thunnus albacares.

Assessment of a rapid HIV test strategy during labor: a pilot study from Rio de Janeiro, Brazil

OBJECTIVES

To use two rapid human immunodeficiency virus (HIV) tests at labor, measure test acceptance and performance, and measure HIV prevalence in these women.

METHODS

Between February and October 2000, two rapid tests (Determine; Abbott, Chicago, IL, U.S.A. and Double Check; Orgenics, Yavne, Israel) were used in three public maternities in Rio de Janeiro, Brazil. Enzyme-linked immunosorbent assay (ELISA) and Western blot (WB) analysis confirmed positive and discordant results.

RESULTS

Of the 858 patients who were enrolled, the mean gestational age was 36 weeks (median = 39, mode = 40) and 17 (2%) refused testing. Of the 841 patients tested, 13 were positive by both tests, which represents a 1.5% prevalence (95% confidence interval: 0.7%-2.3%); all were confirmed by ELISA and WB analysis. Seven samples gave discordant results by the rapid tests; of these, six were ELISA-negative/WB-negative and one was ELISA-negative/WB-indeterminate. The positive predictive value for samples that were positive by both rapid tests simultaneously was 100%.

CONCLUSIONS

Two rapid HIV tests used at labor were well accepted (98%). When the combined results of the two rapid tests (but not a single rapid test) were analyzed, this strategy was as efficient as the standard ELISA and WB HIV strategy for correctly classifying individuals.

A picture of tuberculosis in young Portuguese people in the early 20th century: a multidisciplinary study of the skeletal and historical evidence

The aim of this study was to examine the evidence, and consider the differential diagnosis, for tuberculosis (TB) in juvenile individuals from early 20th century documented skeletons. There are 66 male and female juvenile individuals in the Coimbra Identified Skeletal Collection (CISC) with an age at death ranging from 7-21 years. The individuals died between 1904-1936 in different areas of Coimbra, Portugal. Eighteen of these individuals died from TB affecting different parts of the body. Thirteen (72.2%) showed skeletal lesions that may be related to this infection. Of the 48 individuals with a non-tuberculous cause of death, only 2 (4.2%) had skeletal changes that could be attributed to TB. The distribution of skeletal manifestations caused by the types of TB under study, based on macroscopic and radiological findings, is described and discussed. In addition, the medical records from 6 tuberculous individuals who died in Coimbra University Hospital (CUH) were analysed, and the information, including their diet and access to treatment, is presented. This work, based on data arising before antibiotics became available for treatment, can contribute to the future diagnosis of TB in non-documented skeletal material, and will facilitate a more reliable diagnosis of TB in juvenile individuals.

[Prognosis significance of blood homocysteine after myocardial infarction]

INTRODUCTION AND AIMS

Homocysteinemia is an independent risk factor of coronary artery disease and of myocardial infarction. In the present study we intend to relate fasting homocystein levels to prognosis after a myocardial infarction.

METHODS

From 1990 to 1992, we studied fasting homocysteinemia levels on a group of 112 patients aged under 56 years that had suffered a myocardial infarction between 3 and 12 months before. We obtained, the patients names, addresses, phone numbers and physicians' name. Seven years later (on average) we collected data regarding the patients evolution, consulting medical records, their physicians or by personal contact. We evaluated complications, namely mortality, vascular morbidity, such as unstable angina, re-infarction, stroke, and the need for invasive procedures (catheterism, PTCA, CABG). According to previous studies of the group, we used a cut-point of 10.10 mumol/L to define patients with normal or pathological levels of homocysteinemia. We excluded all patients that took vitamin B supplements, co-factors of HC metabolism, during this follow-up.

RESULTS

We were able to obtain data on 110 patients. Patients with normal HC levels (n = 62) presented less global complications (26 versus 72%, p < 0.0001), non significant tendency to have lower mortality (1.6 versus 6%), had lower morbidity (14 versus 36%, p < 0.01) and lower invasive procedure need (18 versus 48%, p < 0.001). In the group with pathological homocystein levels (n = 48), those with higher homocystein levels presented a higher degree of complications.

CONCLUSIONS

In this population with myocardial infarction under 56 years of age, a high homocysteinemia level is an important prognostic factor. This study suggests that we can improve the prognosis and decrease the complications after myocardial infarction by lowering elevated homocystein levels.

Detection and analysis of apoptosis in peripheral blood cells from breast cancer patients

Apoptosis is a well-known specific process of cell death that normally occurs in physiological situations such as tissue or organ development and involution. During tumor growth there is a balance between proliferation and cell death which involves apoptotic mechanisms. In the present study genomic DNAs from 120 breast tumor biopsies were analyzed by agarose gel electrophoresis and none of them presented the fragmentation pattern characteristic of the apoptosis process. However, 33% of the 105 breast cancer patients clearly showed the apoptotic pattern when DNA from blood cells was analyzed. None of the DNAs from healthy volunteer blood cells showed any trace of apoptosis. Since the breast cancer patients were not receiving chemo- or hormone therapy, the possible relationship between blood cortisol levels and the apoptotic pattern found in patient blood cells was investigated. Using a chemoluminescence immunodetection assay, similar cortisol levels were observed in breast cancer patient sera presenting or not apoptotic blood cells and in healthy volunteer sera. Analysis of the clinical data obtained from 60 of these patients showed that patients bearing tumors of smaller size (under 20 mm) were more susceptible to the apoptotic effect in blood cells. According to the Elston grade, it was observed that 7 of 12 patients with grade III tumors (58%) presented apoptotic peripheral blood cells, in contrast to 10 of 48 patients with grade I and grade II tumors. These observations may reflect the immunosuppression characteristic of some breast cancer patients, which may contribute to tumor growth. Therefore, further studies are necessary to elucidate the factor(s) involved in such massive blood cell death.